Move phosphor depedency into dev

Author: LukeSheard

package.json

@@ -22,6 +22,7 @@
   },
   "homepage": "https://github.com/LukeSheard/phosphor-standalone#readme",
   "devDependencies": {
+    "@phosphor/widgets": "^1.5.0",
     "@types/extract-text-webpack-plugin": "^3.0.0",
     "@types/node": "^8.5.2",
     "@types/webpack": "^3.8.1",
@@ -34,7 +35,7 @@
     "typescript": "^2.6.2",
     "webpack": "^3.10.0"
   },
-  "dependencies": {
-    "@phosphor/widgets": "^1.5.0"
-  }
+  "bundledDependencies": [
+    "@phosphor/widgets"
+  ]
 }